Mr Preval takes Mr Sarkozy on an aerial tour of quake-torn Haiti
French President Nicolas Sarkozy has pledged earthquake-ravaged Haiti 270m euros (£235m) in reconstruction aid.
Mr Sarkozy, the first French president to visit the former colony, was greeted by Haitian President Rene Preval in the capital, Port-au-Prince.
His schedule includes a visit to a field hospital and a helicopter tour to see the devastation of the quake, which killed up to 230,000.
The aid package includes cancelling 56m euros (£48m) in debt owed by Haiti.
"I have come to tell the Haitian people and their leaders that France, which was the first on the ground after the catastrophe, will remain firmly at their side to help them pick themselves up again and open a new happy page in their history," said Mr Sarkozy after his arrival.
Mr Preval said: "Under other circumstances, a visit by a president of the French Republic would have been a pleasure", but added that instead this was "a time of national mourning. We are grieving for our dead."
The two men then boarded a helicopter to view the devastation and the aid efforts from the air.
The Inter-American Development Bank has estimated the damages from the quake at up to $14bn (£8.9bn; 12.2bn euros).
More than one million people were left homeless and aid workers are rushing to distribute tarpaulins ahead of the rainy season.
France will be part of a major summit in New York next month to develop international aid efforts.
The legacy of French colonial rule is still a bitter issue for many Haitians.
Haiti won independence in 1804 after a bloody uprising by slaves against the French.
However, Paris demanded 90 million pieces of gold in reparations for lost property and Haiti did not finish repaying the debt until 1947.
French and Haitian officials hope Mr Sarkozy's four-and-a-half hour visit will cement better relations.
Mr Sarkozy said: "France will live up to the responsibilities of its shared history and friendship with Haiti."
As part of his trip, the French president will also visit Martinique and French Guyana.